81925881797 has 2 divisors, whose sum is σ = 81925881798. Its totient is φ = 81925881796.

The previous prime is 81925881781. The next prime is 81925881883. The reversal of 81925881797 is 79718852918.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 76556802721 + 5369079076 = 276689^2 + 73274^2 .

It is a cyclic number.

It is not a de Polignac number, because 81925881797 - 2⁴ = 81925881781 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81925889797) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40962940898 + 40962940899.

It is an arithmetic number, because the mean of its divisors is an integer number (40962940899).

Almost surely, 2^81925881797 is an apocalyptic number.

It is an amenable number.

81925881797 is a deficient number, since it is larger than the sum of its proper divisors (1).

81925881797 is an equidigital number, since it uses as much as digits as its factorization.

81925881797 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20321280, while the sum is 65.

The spelling of 81925881797 in words is "eighty-one billion, nine hundred twenty-five million, eight hundred eighty-one thousand, seven hundred ninety-seven".